System and method for a compressor

ABSTRACT

Systems and methods of the invention relate to diagnosing a compressor. A method may include monitoring a crankcase pressure of a compressor, analyzing the monitored crankcase pressure, and identifying a condition of the compressor based on the analysis of the monitored crankcase pressure. A system is also disclosed including an engine, a compressor operatively connected to the engine, and a controller that is operable to identify a condition of the compressor.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application Ser. No. 61/636,192, filed Apr. 20, 2012, and entitled “SYSTEM AND METHOD FOR A COMPRESSOR.” The entirety of the aforementioned application is incorporated herein by reference.

BACKGROUND

1. Technical Field

Embodiments of the subject matter disclosed herein relate to compressor diagnostics.

2. Discussion Of Art

Compressors compress gas, such as air. Compressors may be driven by electric motors, and may be air cooled. Some compressors include three cylinders with two stages. For example, a compressor can have two low pressure cylinders which deliver an intermediate pressure air supply to a single high pressure cylinder for further compression for final delivery to an air reservoir. Compressor and compressor components are subject to various failure modes, which increase difficulties in maintaining a healthy compressor.

It may be desirable to have a system and method that differs from those systems and methods that are currently available.

BRIEF DESCRIPTION

In an embodiment, a method (e.g., a method for controlling and/or operating a compressor) is provided that includes the steps of monitoring a crankcase pressure of a compressor; analyzing the monitored crankcase pressure; and identifying a condition of the compressor based on the analysis of the monitored crankcase pressure. (The method may be carried out automatically or otherwise by a controller.)

Another embodiment relates to a controller that is operable in association with a compressor (e.g., the controller may receive data from and/or about the compressor and control the compressor or other systems based on the data). The controller is configured to receive a signal corresponding to a monitored pressure within a crankcase of the compressor, and to analyze the monitored crankcase pressure. The controller can further be configured to identify a condition of the compressor based on the analysis of the monitored crankcase pressure.

In an embodiment, a system comprises a compressor operatively connected to an engine, wherein the compressor includes a crankcase having a crankcase pressure sensor. The system further comprises a controller that is configured to receive a signal corresponding to a monitored pressure within the crankcase of the compressor from the crankcase pressure sensor. The controller is further configured to analyze the monitored crankcase pressure and to identify a condition of the compressor based on the analysis of the monitored crankcase pressure.

In an embodiment, a compressor system is provided that includes means for monitoring a crankcase pressure of a compressor and means for analyzing the monitored crankcase pressure. The compressor system further includes means for identifying a condition of the compressor based on the analysis of the monitored crankcase pressure.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference is made to the accompanying drawings in which particular embodiments and further benefits of the invention are illustrated as described in more detail in the description below, in which:

FIG. 1 is an illustration of an embodiment of a vehicle system with a compressor;

FIG. 2 is an illustration of an embodiment of system that includes a compressor;

FIG. 3 is a graph depicting a measured crankcase pressure for a compressor;

FIG. 4 is a graph depicting a measured crankcase pressure for a compressor;

FIG. 5 is an illustration of an embodiment of a system that includes a compressor;

FIG. 6 is a graph depicting a measured crankcase pressure for a compressor; and

FIG. 7 is a flow chart of an embodiment of a method for identifying a condition of a compressor based upon a measured crankcase pressure.

DETAILED DESCRIPTION

Embodiments of the subject matter disclosed herein relate to systems and methods that facilitate identifying a leak condition or other condition within a compressor and, in particular, identifying a leak condition by monitoring a crankcase pressure. A controller can be configured to identify a compressor condition based upon the monitored crankcase pressure. Moreover, a crankcase pressure sensor (e.g., also referred to more generally as a detection component) can be configured to monitor crankcase pressure for the compressor, for purposes of detecting a change (e.g., a fluctuation, increase, decrease, among others) in the pressure. Based upon a detected change in the monitored crankcase pressure, the controller can be configured to determine a condition of the compressor. In an embodiment, the controller can be further configured to communicate an alert related to the detected change in the crankcase pressure. The alert can be a signal (e.g., diagnostic code, audio, text, visual, haptic, among others) that indicates a change in the monitored pressure of the crankcase of the compressor. This alert can be utilized to provide maintenance on the compressor or a portion thereof. In an embodiment, the controller can be configured to schedule a maintenance operation based upon the detected change in crankcase pressure and/or the communicated alert in order to perform preventative maintenance. Still further, the controller can be configured to automatically or otherwise control the compressor based on and/or responsive to monitored air pressure.

With reference to the drawings, like reference numerals designate identical or corresponding parts throughout the several views. However, the inclusion of like elements in different views does not mean a given embodiment necessarily includes such elements or that all embodiments of the invention include such elements.

The term “component” as used herein can be defined as a portion of hardware, a portion of software, or a combination thereof. A portion of hardware can include at least a processor and a portion of memory, wherein the memory includes an instruction to execute. The term “vehicle” as used herein can be defined as any asset that is a mobile machine that transports at least one of a person, people, or a cargo, or that is configured to be portable from one location to another. For instance, a vehicle can be, but is not limited to being, a locomotive or other rail vehicle, an intermodal container, a marine vessel, a mining equipment, a stationary portable power generation equipment, an industrial equipment, a construction equipment, and the like. The term “loaded” as used herein can be defined as a compressor system mode where air is being compressed into the reservoir. The term “loaded start” as used herein can be defined as a compressor system mode in a loaded condition during a starting phase of the compressor. The term “unloaded” as used herein can be defined as a compressor system mode where air is not being compressed into the reservoir.

A compressor compresses gas, such as air. In some embodiments, the compressed gas is supplied to operate pneumatic or other equipment powered by compressed gas. A compressor may be used for mobile applications, such as vehicles. By way of example, vehicles utilizing compressors include locomotives, on-highway vehicles, off-highway vehicles, mining equipment, and marine vessels. In other embodiments, a compressor may be used for stationary applications, such as in manufacturing or industrial applications requiring compressed air for pneumatic equipment among other uses. The compressor depicted in the below figures is one which utilizes spring return inlet and discharge valves for each cylinder, wherein the movement of these valves is caused by the differential pressure across each cylinder as opposed to a mechanical coupling to the compressor crank shaft. The subject invention can be applicable to machines with either type of valve (e.g., spring return valves, mechanical coupled valves, among others) and the spring return valve is depicted solely for example and not to be limiting on the subject innovation.

The components of a compressor may degrade over time resulting in performance reductions and/or eventual failure of a compressor. In vehicle applications, for example, a compressor failure may produce a road failure resulting in substantial costs to the vehicle owner or operator. In this context, a road failure includes a vehicle, such as a locomotive, becoming inoperative when deployed in service as a result of the failure or degradation of a compressor system that prevents operation or requires shutting down the vehicle until repairs can be made. Prior to a total failure, the detection of degraded components or other deterioration of the compressor may be used to identify incipient faults or other conditions indicative of deterioration. In response to detecting such conditions, remedial action may be taken to mitigate the risk of compressor failure and associated costs.

The systems and methods presently disclosed can also be used to diagnose and/or prognose problems in a compressor prior to total compressor failure. If deterioration or degradation of the compressor is detected in the system, action can be taken to reduce progression of the problem and/or further identify the developing problem. In this manner, customers realize a cost savings by prognosing compressor problems in initial stages to reduce the damage to compressor components and avoid compressor failure and unplanned shutdowns. Moreover, secondary damage to other compressor components (e.g., pistons, valves, liners, and the like) or damage to equipment that relies upon the availability of the compressed gas from the compressor may be avoided if compressor problems are detected and addressed at an early stage.

FIG. 1 illustrates a block diagram of an embodiment of a vehicle system 100. The vehicle system 100 is depicted as a rail vehicle 106 (e.g., a locomotive) configured to run on a rail 102 via a plurality of wheels 108. The rail vehicle includes a compressor system with a compressor 110. In an embodiment, the compressor is a reciprocating compressor that delivers air at high pressure. In another embodiment, the compressor is a reciprocating compressor with a bi-directional drive system that drives a piston in a forward direction and the reverse direction. In an embodiment, the compressor receives air from an ambient air intake 114. The air is then compressed to a pressure greater than the ambient pressure and the compressed air is stored in reservoir 180, which is monitored by a reservoir pressure sensor 185. In one embodiment, the compressor is a two-stage compressor (such as illustrated in FIG. 2) in which ambient air is compressed in a first stage to a first pressure level and delivered to a second stage, which further compresses the air to a second pressure level that is higher than the first pressure level. The compressed air at the second pressure level is stored in a reservoir. The compressed air may then be provided to one or more pneumatic devices as needed. In other embodiments, the compressor 110 may be a single stage or multi-stage compressor.

The compressor includes a crankcase 160. The crankcase is an enclosure for a crankshaft (not shown in FIG. 1) connected to cylinders (not shown in FIG. 1) of the compressor. A motor 104 (e.g., electric motor) is employed to rotate the crankshaft to drive the pistons within the cylinders. In another embodiment, the crankshaft may be coupled to a drive shaft of an engine or other power source configured to rotate the crankshaft of the compressor. In each embodiment, the crankshaft may be lubricated with compressor oil that is pumped by an oil pump (not shown) and sprayed onto the crankshaft. The crankshaft is mechanically coupled to a plurality of pistons via respective connecting rods. The pistons are drawn and pushed within their respective cylinders as the crankshaft is rotated to compress a gas in one or more stages.

The rail vehicle further includes a controller 130 for controlling various components related to the vehicle system. In an embodiment, the controller is a computerized control system with a processor 132 and a memory 134. The memory may be computer readable storage media, and may include volatile and/or non-volatile memory storage. In an embodiment, the controller includes multiple control units and the control system may be distributed among each of the control units. In yet another embodiment, a plurality of controllers may cooperate as a single controller interfacing with multiple compressors distributed across a plurality of vehicles. Among other features, the controller may include instructions for enabling on-board monitoring and control of vehicle operation. Stationary applications may also include a controller for managing the operation of one or more compressors and related equipment or machinery.

In an embodiment, the controller receives signals from one or more sensors 150 to monitor operating parameters and operating conditions, and correspondingly adjust actuators 152 to control operation of the rail vehicle and the compressor. In various embodiments, the controller receives signals from one or more sensors corresponding to compressor speed, compressor load, boost pressure, exhaust pressure, ambient pressure, exhaust temperature, or other parameters relating to the operation of the compressor or surrounding system. In another embodiment, the controller receives a signal from a crankcase pressure sensor 170 that corresponds to the pressure within the crankcase. In yet another embodiment, the controller receives a signal from a crankshaft position sensor 172 that indicates a position of the crankshaft. The position of the crankshaft may be identified by the angular displacement of the crankshaft relative to a known location such that the controller is able to identify the position of each piston within its respective cylinder based upon the position of the crankshaft. In some embodiments, the controller controls the vehicle system by sending commands to various components. On a locomotive, for example, such components may include traction motors, alternators, cylinder valves, and throttle controls among others. The controller may be connected to the sensors and actuators through wires that may be bundled together into one or more wiring harnesses to reduce space in vehicle system devoted to wiring and to protect the signal wires from abrasion and vibration. In other embodiments, the controller communicates over a wired or wireless network that may allow for the addition of components without dedicated wiring.

The controller may include onboard electronic diagnostics for recording operational characteristics of the compressor. Operational characteristics may include measurements from sensors associated with the compressor or other components of the system. Such operational characteristics may be stored in a database in memory. In one embodiment, current operational characteristics may be compared to past operational characteristics to identify trends of compressor performance.

The controller may include onboard electronic diagnostics for identifying and recording potential degradation and failures of components of vehicle system. For example, when a potentially degraded component is identified, a diagnostic code may be stored in memory. In one embodiment, a unique diagnostic code may correspond to each type of degradation that may be identified by the controller. For example, a first diagnostic code may indicate a malfunctioning exhaust valve of a cylinder, a second diagnostic code may indicate a malfunctioning intake valve of a cylinder, a third diagnostic code may indicate deterioration of a piston or cylinder resulting in a blow-by condition. Additional diagnostic codes may be defined to indicate other deteriorations or failure modes. In yet other embodiments, diagnostic codes may be generated dynamically to provide information about a detected problem that does not correspond to a predetermined diagnostic code. In some embodiments, the controller modifies the output of charged air from the compressor, such as by reducing the duty cycle of the compressor, based on parameters such as the condition or availability of other compressor systems (such as on adjacent locomotive engines), environmental conditions, and overall pneumatic supply demand.

The controller may be further linked to display 140, such as a diagnostic interface display, providing a user interface to the operating crew and/or a maintenance crew. The controller may control the compressor, in response to operator input via user input controls 142, by sending a command to correspondingly adjust various compressor actuators. Non-limiting examples of user input controls may include a throttle control, a braking control, a keyboard, and a power switch. Further, operational characteristics of the compressor, such as diagnostic codes corresponding to degraded components, may be reported via display to the operator and/or the maintenance crew.

The vehicle system may include a communications system 144 linked to the controller. In one embodiment, communications system may include a radio and an antenna for transmitting and receiving voice and data messages. For example, data communications may be between vehicle system and a control center of a railroad, another locomotive, a satellite, and/or a wayside device, such as a railroad switch. For example, the controller may estimate geographic coordinates of a vehicle system using signals from a GPS receiver. As another example, the controller may transmit operational characteristics of the compressor to the control center via a message transmitted from communications system. In one embodiment, a message may be transmitted to the command center by communications system when a degraded component of the compressor is detected and the vehicle system may be scheduled for maintenance.

As discussed above, the term “loaded” refers to a compressor mode where air is being compressed into the reservoir. The compressor depicted is one which utilizes spring return inlet and discharge valves for each cylinder in which the movement of these valves is caused by the differential pressure across them as opposed to a mechanical coupling to the compressor crank shaft. The subject disclosure may be applicable to machines with either type of valve, but the spring return type will be illustrated here for the sake of brevity.

The controller can be configured to adjust at least one of the following: an operation of the compressor; a scheduled maintenance for the compressor; a maintenance for the compressor; a service for the compressor; a diagnostic code of the compressor; an alert for the compressor; among others. In an embodiment, the controller can be configured to adjust the compressor based upon a detection of a change in pressure for the crankcase. In a more particular embodiment, the controller can be configured to adjust the compressor based upon a monitored change in pressure in combination with a position of a piston of the compressor.

The compressor 110 can include a detection component 128 that can be configured to detect at least one of a pattern, a signature, a level, among others related to a crankcase pressure measured, wherein such detection is indicative of a leak condition for the compressor. In particular, the leak condition can relate to crankcase breather valve or blow-by condition (discussed in more detail below). The detection component and/or the pressure sensor (e.g., pressure sensor 170) can be employed with the compressor to collect pressure data that is indicative of a leak condition. In an embodiment, the controller can be configured to adjust the compressor based upon the detection component and/or the pressure sensor.

The detection component can be a stand-alone component (as depicted), incorporated into the controller component, or a combination thereof. The controller component can be a stand-alone component (as depicted), incorporated into the detection component, or a combination thereof. In another embodiment, the detection component and/or the pressure sensor can be a stand-alone component (as depicted), incorporated into the controller component, or a combination thereof.

FIG. 2 illustrates a detailed view of the compressor set forth in FIG. 1 above. The compressor includes three cylinders 210, 220, 230. Each cylinder contains a piston 218, 228, 238 that is coupled to a crankshaft 250 via connecting rods 240, 242, 244. The crankshaft is driven by the motor to cyclically pull the respective pistons to a Bottom-Dead-Center (BDC) and push the pistons to a Top-Dead-Center (TDC) to output charged air, which is delivered to the reservoir via air lines 280, 282, 284, 286. In this embodiment, the compressor is divided into two stages: a low pressure stage and a high pressure stage to produce charged air in a stepwise approach. The low pressure stage compresses air to a first pressure level which is further compressed by the high pressure stage to a second pressure level. In this example, the low pressure stage includes cylinders 220, 230 and the high pressure stage includes cylinder 210.

In operation, air from the ambient air intake is first drawn into the low pressure cylinders via intake valves 222, 232, which open and close within intake ports 223, 233. The ambient air is drawn in as the low pressure cylinders are pulled towards BDC and the intake valves 222, 232 separate from intake ports 223, 233 to allow air to enter each cylinder 220, 230. Once the pistons reach BDC, the intake valves 222, 232 close the intake ports 223, 233 to contain air within each cylinder. Subsequently, pistons 228, 238 are pushed toward TDC, thereby compressing the ambient air initially drawn into the cylinders. Once the cylinders have compressed the ambient air to a first pressure level, exhaust valves 224, 234 within exhaust ports 225, 235 are opened to release the low pressure air into low pressure lines 280, 282.

The air compressed to a first pressure level is routed to an intermediate stage reservoir 260. The intermediate stage reservoir 260 received air from one stage of a multistage compressor and provides the compressed air to a subsequent stage of a multistage compressor. In an embodiment, the intermediate stage reservoir 260 is a tank or other volume connected between successive stages by air lines. In other embodiments, the air lines, such as low pressure lines 280, 282 provide sufficient volume to function as an intermediate stage reservoir without the need for a tank or other structure.

In an embodiment, the compressor system also includes an intercooler 264 that removes the heat of compression through a substantially constant pressure cooling process. One or more intercoolers may be provided along with one or more intercooler controllers 262. In some embodiments, the intercooler 264 is integrated with the intermediate stage reservoir 260. A decrease in the temperature of the compressed air increases the air density allowing a greater mass to be drawn into the high pressure stage increasing the efficiency of the compressor. The operation of the intercooler is controlled by the intercooler controller 262 to manage the cooling operation. In an embodiment, the intercooler controller 262 employs a thermostatic control through mechanical means such as via thermal expansion of metal. In a multistage compressor system having more than two stages, an intercooler may be provided at each intermediate stage.

The air at a first pressure level (e.g., low pressure air) is exhausted from the intercooler into low pressure air line 284 and subsequently drawn into the high pressure cylinder 210. More particularly, as piston 218 is pulled toward BDC, the intake valve 212 opens, thereby allowing the low pressure air to be drawn into the cylinder 210 via intake port 213. Once the piston 218 reaches BDC, the intake valve 212 closes to seal the low pressure air within the cylinder 210. The piston is then pushed upward thereby compressing the low pressure air into high pressure air. High pressure air is air at a second pressure level greater than the first pressure level, however the amount of compression will vary based upon the requirements of the application. As compression increases, the exhaust valve 214 is opened to allow the high pressure air to exhaust into high pressure line 286 via exhaust port 215. An aftercooler 270 cools the high pressure air to facilitate a greater density to be delivered to the reservoir via high pressure air line 288.

The above process is repeated cyclically as the crankshaft 250 rotates to provide high pressure air to the reservoir 180, which is monitored by the reservoir pressure sensor 185. Once the reservoir reaches a particular pressure level (e.g., 140 psi), the compressor operation is discontinued.

In some embodiments, the compressor includes one or more valves configured to vent compressed air from intermediate stages of the compressor system. The unloader valves and/or relief valves may be operated after compressor operations are discontinued, or may be operated during compressor operations to relieve pressure in the compressor system. In an embodiment, an unloader valve 268 is provided in the intermediate stage reservoir 260 and configured to vent the low pressure compressed air from the intermediate stage reservoir, low pressure air lines 280, 282 and intercooler 264. Venting compressed air reduces stress on system components during periods when the compressor is not in use and may extend the life of the system. In another embodiment, the unloader valve 268 operates as a relief valve to limit the buildup of pressure in the intermediate stage reservoir 260. In yet another embodiment, intake valves 222, 232 operate as unloader valves for the cylinders 220, 230 allowing compressed air in the cylinders to vent back to the ambient air intake 114. In another embodiment, the system 200 can include relief valves such as breather valve 174, a relieve valve on the intercooler 264 (shown in FIG. 4), a relieve valve for air line 286, a rapid unloader valve on the intercooler 264 (shown in FIG. 4)

A compressor, such as the compressor illustrated in FIG. 2, operates to charge the reservoir 180 with compressed air or other gas. Once the compressor charges the reservoir to a determined pressure value the compressor operation is discontinued. In some embodiments, when compressor operations are discontinued, one or more unloader valves are opened to vent intermediate stages of the compressor to the atmosphere. The intake valves of the cylinders as well as unloader valves of the intermediate stage reservoirs may all operate as unloader valves to vent the cylinders of the compressor to the atmosphere. Once the unloader valves are actuated and the cylinders and intermediate stages of the compressor have been vented to the atmosphere the pressure within the reservoir is expected to remain constant as previously discussed.

The compressor 110 can include additional features and/or components that are not illustrated in FIGS. 1 and 2. For instance, the system may include a Control Mag Valve (CMV), a Thermostatically Controlled Intercooler System (TCIS) bypass, a rapid unloader valve, an unloader valve for cylinder 230, an unloader valve for cylinder 220, a relief valve(s), among others.

The crankshaft can include a first end opposite a second end in which the first end is coupled to one or more connecting rods for each respective cylinder. The crankshaft, cylinders, and pistons are illustrated in BDC position based upon the location of the first end. BDC position is a location of the first end at approximately negative ninety degrees (−90 degrees) or 270 degrees. A TDC position is a location of the first end at approximately ninety degrees (90 degrees) or −270 degrees.

As discussed above, the controller can be configured to employ an adjustment to the compressor based upon at least one of a detected change of pressure in the crankcase or a detected change of pressure in the crankcase correlated with a position of a piston. In embodiment, the pressure sensor can monitor a pressure for the crankcase with or without a cycling of a piston. Upon detection of a change in the pressure of the crankcase, the controller can implement an adjustment to the compressor and/or communicate an alert based on the detected change.

Referring now to FIGS. 3-6, an embodiment of a method and/or employment of a system for a compressor is illustrated. In an embodiment, a method for a compressor includes monitoring a crankcase pressure of a compressor, analyzing the monitored crankcase pressure, and identifying a condition of the compressor based on the analysis of the monitored crankcase pressure. When a reciprocating compressor is operating, such as the compressor 110 shown in FIG. 2, the crankshaft 250 rotates causing the pistons 218, 228, 238 to move within their respective cylinders. As the pistons move through each revolution, the effective volume of the crankcase 160 changes.

For ease of illustration, a crankcase pressure 350 of a single stage compressor having only one cylinder, such as cylinder 210, is illustrated in graph 300 of FIG. 3. As the piston rises on a compression stroke the effective volume of the crankcase increases (e.g., due to the volume of the piston leaving the crankcase) resulting in a drop in crankcase pressure as measured by a crankcase pressure sensor, such as crankcase pressure sensor 170. The crankcase pressure 350 falls until the piston reaches top dead center at which point the crankcase pressure reaches a minimum as shown by a trough 352. As the piston moves through a suction stroke the effective volume of the crankcase is reduced resulting in an increase in crankcase pressure. The crankcase pressure 350 rises until the piston reaches bottom dead center at which point the crankcase pressure reaches a peak 354. As illustrated in FIG. 3, crankcase pressure rises and falls corresponding to the position of the piston within the cylinder with a period 362 corresponding to one revolution of the piston. In a multistage compressor, such as a compressor having two or more cylinders, the movement of each piston affects the crankcase pressure in a similar manner. In the compressor illustrated in FIG. 2, each of the three pistons 218, 228, 238 would produce similar periodic pressure variations that would be offset from each other depending upon the configuration of the crankshaft. The corresponding crankcase pressure would therefore reflect multiple peaks and troughs correlated to the positions of one, two or more pistons of the compressor. In multi-stage compressor, the crankcase pressure may be correlated with an indication of the position of one or more of the pistons to identify the effect that each piston has on the crankcase pressure. Using the correlation, a condition of one of the plurality of cylinders of the compressor may be determined

As shown in graph 300 of FIG. 3, in a healthy compressor system the crankcase pressure 350 is typically maintained below atmospheric pressure, which is indicated as “0”. In various embodiments, the compressor includes a crankcase breather valve, such as breather valve 174 in FIG. 2, which regulates crankcase pressure by permitting air to exit the crankcase when crankcase pressure rises and limiting air entering the crankcase when crankcase pressure falls. In this manner, excessive pressure within the crankcase is avoided so as to improve the efficiency of the compressor system. As a result, the average crankcase pressure during operation of the compressor system is maintained in the desired range.

In one embodiment, analyzing the monitored crankcase pressure includes calculating an average of the crankcase pressure over a time period and comparing the average crankcase pressure to a nominal crankcase average pressure. The condition of the compressor may then be determined (e.g., identified) based on the difference between the calculated crankcase average pressure and the nominal crankcase average pressure. In an embodiment, the nominal crankcase average pressure is the expected average pressure based upon the design of the compressor and crankcase. The nominal crankcase average pressure may be determined from empirical tests to establish a baseline when the compressor is new or otherwise known to be operating correctly. The baseline may be stored in memory and compared to the actual crankcase average pressure periodically to monitor compressor operations. In yet another embodiment, the nominal crankcase average pressure is calculated based upon environmental or operating conditions. For example, in some designs the crankcase pressure may vary based on ambient air temperature or ambient air pressure. The nominal crankcase average pressure may thus be adjusted to account for such environmental conditions. In other embodiments, one or more of the compressor operating speed, the reservoir pressure or the compressor oil temperature are correlated to the nominal or expected crankcase average compressor. In yet other embodiments, the nominal crankcase pressure is a predetermined limit which if exceeded requires compressor operation to be discontinued. The nominal crankcase average pressure may therefore be determined from at least one or more of these or other environmental or operating parameters of the compressor.

In a healthy compressor system, the crankcase average pressure and correlation of the crankcase pressure to the position of the piston may remain substantially constant as illustrated in graph 300 of FIG. 3. The failure or degradation of the breather valve however may interfere with the proper regulation of crankcase pressure. If the breaker valve becomes clogged, air is not released as crankcase pressure rises resulting in a shift in the measured crankcase pressure, such as illustrated in graph 400 of FIG. 4. As shown, the periodic peaks 360 and troughs 358 correlated with piston movement are still detectable in a measured crankcase pressure 356 (also referred to as crankcase pressure 356). The crankcase average pressure however rises as the breather valve is unable to vent the excess pressure within the crankcase. In this manner, a crankcase breather valve failure is identified by the increased average pressure, and appropriate maintenance or repair operations may be scheduled. Over time, the increased crankcase average pressure may result in damage to the seals and other components of the compressor system, and if unchecked could render the compressor system inoperative. Increased crankcase pressure may also reduce the efficiency of the compressor system by pushing against each piston as the piston is pulled through its suction stroke increasing the load on the motor 104 or other power source driving the crankshaft 250.

In other embodiments, a method for a compressor that includes monitoring the crankcase pressure is used to identify other compressor failure modes. In one embodiment, a condition of one of a plurality of cylinders is identified based on the correlation of the monitored crankcase pressure and the indication of the position of the piston in the cylinder of a reciprocating compressor. During operation, air is compressed within the cylinder as the piston travels through a compression stroke to fill the reservoir 180 with compressed air. In order to maintain efficient operation, the volume of the cylinder in which compression occurs is substantially sealed, such as with a lining or seal may be used to limit leakage of air as the piston travels within the cylinder.

Referring now to system 500 of FIG. 5, the high pressure cylinder 210 of FIG. 2 is illustrated during a compression stroke. During at least a portion of the compression stroke of the piston 218, the intake valve 212 is closed sealing the intake port 213, and the exhaust valve 214 is closed sealing the exhaust port 215. With the intake and exhaust ports sealed, the internal volume of the cylinder 210 is expected to be substantially sealed such that the air within the cylinder can be compressed. As a result of wear between the piston 218 and a cylinder inner wall 290 or other degradation in the lining or seals used to maintain the closed volume, air may leak between the piston 218 and the cylinder inner wall 290 into the crankcase 160 as illustrated by arrows 370. Wear of the piston or cylinder wall may result from a variety of problems, such as misalignment of the piston or operating without sufficient lubricating oil or at excessive oil temperatures. In addition, seals or cylinder linings may degrade as a result of excess crankcase pressure, such as may be caused by the failure of a breather valve as previously discussed. Regardless of the underlying cause, a piston blow-by condition develops when air escapes from the cylinder 210 passed the piston 218 and into the crankcase 160 (as illustrated by arrows 370).

The flow of air into the crankcase resulting from a piston blow-by condition affects the crankcase pressure measured by the crankcase pressure sensor 170. By way of illustration, graph 600 of FIG. 6 illustrates a healthy crankcase pressure 372 analogous to that illustrated in graph 300 of FIG. 3. When a cylinder has been degraded, the crankcase pressure may develop a blow-by indication 374. In one embodiment, the blow-by indication 374 is an increase in measured crankcase pressure during the compression stroke of a piston. Using crankshaft position sensor 172, the position of each piston may be determined such that the compression stroke of each position is identified. By correlating the identified blow-by condition 374 with the compression stroke of a given piston, a blow-by condition of a given cylinder is identified. The identification of a specific cylinder in which the blow-by condition is occurring facilitates repairs and improves the efficiency of maintenance operations.

In addition to identifying the existence of a blow-by condition, the severity of the blow-by condition may be assessed. As illustrated in graph 600 of FIG. 6, a blow-by condition may present as an increase in crankcase pressure during a compression stroke. In other embodiments where the blow-by condition is less severe, the blow-by indication may be a reduction in the decrease of crankcase pressure during a compression stroke. Stated another way, a reduction in the difference between the peaks 376 and troughs 378 of the measured crankcase pressure may indicate a blow-by condition even if the crankcase pressure does not rise during the compression stroke.

The illustrations of monitored crankcase pressure in graphs 300, 400, and 600 in FIGS. 3-4, and 6 respectively, demonstrate the effects of a single cylinder. In compressor systems having two or more cylinders, each cylinder produces a similar effect on crankcase pressure such that the resulting crankcase pressure reflects the combination of those effects. In another embodiment, the monitored crankcase pressure is analyzed by identifying the frequency content of the monitored crankcase pressure at one or more known frequencies. The known frequencies are determined based on the rate at which the compressor is operated. As noted above, the monitored crankcase pressure is expected to rise and fall as the piston cycles within the cylinder. The monitored crankcase pressure thus includes a periodic variation that corresponds to a once-per-revolution signature associated with the movement of the piston. As shown in graph 600 of FIG. 6, a piston blow-by condition may produce an additional peak 374 (also referred to as a blow-by condition). The blow-by condition is therefore identifiable in a frequency analysis based upon the rate at which the compressor is operated. In one embodiment, the blow-by condition may result in a detectable change in the once-per-revolution signature. In other embodiments, the blow-by condition may result in a detectable twice-per-revolution signature. A range of frequency components related to the compressor operating speed may also be generated as the crankcase pressure is affected by one or more pistons, one or more blow-by conditions, breather valve failures, or other effects during operation of the compressor. In this manner, a frequency analysis of the monitored crankcase pressure is used to determine (e.g., identify) the condition of the compressor. The frequency analysis may be used in addition or as an alternative to time domain analysis of the monitored crankcase pressure. To further assist in identifying faults, crankcase pressure is monitored under different operating conditions, such as at different reservoir pressure levels, and when the pistons are cycled under loaded and unloaded conditions. In this manner, the methods for a compressor presently disclosed provide advanced detection of faults and facilitate troubleshooting and repair by identifying the nature of the failure and the likely components at fault.

In yet another embodiment, a controller is provided to determine a condition of a compressor. The controller is configured to receive a signal corresponding to a monitored pressure within a crankcase of a compressor. In an embodiment, the controller is configured to communicate with one or more crankcase pressure sensors 170 and receive the signal corresponding to the monitored pressure from the one or more crankcase pressure sensors. The controller is also configured to analyze the monitored crankcase pressure and determine a condition of the compressor based on the analysis of the monitored crankcase pressure. In one embodiment, the controller performs a frequency analysis and identifies frequency components in the monitored crankcase pressure based upon the rate at which the compressor is operated.

In another embodiment, the controller correlates the monitored crankcase pressure with an indication of a position of a piston in a cylinder of the compressor. The controller may communicate with the crankshaft position sensor 172 to determine the position of the piston in the cylinder. In an embodiment, the controller is integral with a vehicle system, such as controller 130. In yet another embodiment, the controller is provided with a test kit used for maintenance and repair or diagnostic operations. In this manner, the controller may be further configured to actuate the compressor in either a loaded or unloaded condition while monitoring crankcase pressure. In embodiments, the controller is able to identify a blow-by condition of at least one cylinder of the compressor and identity a crankcase breather valve failure by analyzing the measured crankcase pressure as described above. The controller may include a processor and may be configured to calculate an average of the crankcase pressure over a time period, and compare the average crankcase pressure over the time period to a nominal crankcase average pressure. In some embodiments, the time period is determined by the operator, however in other embodiments, the time period is determined by the controller based on operating conditions of the compressor. In some applications, the measured crankcase pressure will also be influenced by vibrations and noise from related system components. By averaging the measured crankcase pressure over a time period, such influences may be reduced providing a more accurate assessment of crankcase pressure.

When a fault is detected, such as a blow-by condition or a breather valve failure, a variety of steps may be taken to reduce further degradation of the compressor system. In one embodiment, a signal is generated in response to determining a condition of the compressor based on the analysis of the monitored crankcase pressure. The generated signal may indicate a severity level of the condition, such as the severity of a blow-by condition as indicated by the rise in crankcase pressure during a compression stroke of a piston. In an embodiment, in response to the signal, the duty cycle of the compressor is reduced in order to reduce further degradation of the compressor until repairs can be made. The duty cycle may be reduced by a fixed amount, such as by 25%, 50% or more, or may be reduced in proportion to the severity of the identified failure. If the leak condition is severe, power to the compressor may be disconnected such that the compressor ceases operating until appropriate repairs have been effected. In another embodiment, personnel are notified by an audio alarm, a visual alarm, a text message, an email, an instant message, a phone call, or other method appropriate for the operating environment. In a system having multiple compressors, in response to a detected leak on one compressor the operation of the other compressors may be adjusted to compensate for the reduced performance of one compressor allowing the system to remain functional until repairs can be scheduled.

In various other embodiments, the aspects of the systems and methods previously described may also be employed individually or in combination to diagnose the condition of a compressor. In one embodiment, a method for diagnosing a compressor includes operating a compressor in an unloaded condition by cycling the pistons within their respective cylinders, monitoring at least the reservoir pressure and the crankcase pressure, and determining a condition of the compressor based on an analysis of both the monitored reservoir pressure and crankcase pressure. In another embodiment, a method for diagnosing a compressor includes operating a multi-stage compressor to charge a reservoir with compressed air, monitoring at least a crankcase pressure and an intermediate stage pressure, and determining a condition of the compressor based on an analysis of both the monitored crankcase pressure and the monitored intermediate stage pressure. In yet another embodiment, a method for diagnosing a compressor includes monitoring signals from at least two of a primary reservoir pressure sensor, an intermediate reservoir pressure sensor, a crankcase pressure sensor, and a crankshaft position sensor, and correlating the monitored signals to identify a failure condition of the compressor. In yet another embodiment, a method of diagnosing a compressor includes actuating an unloader valve, monitoring at least a reservoir pressure sensor and a crankshaft position sensor, and identifying a leak condition of a valve disposed between a cylinder and a reservoir of a compressor. By way of example and not limitation, the subject disclosure can be utilized alone or in combination with a system and/or method disclosed in U.S. Provisional Application Ser. No. 61/636,192, filed Apr. 20, 2012, and entitled “SYSTEM AND METHOD FOR A COMPRESSOR” in which the entirety of the aforementioned application is incorporated herein by reference.

The methods and systems disclosed herein may be applied to a reciprocating compressor having one or more compressor stages, such as the compressor illustrated in FIG. 2. In other embodiments, the methods and systems may be applied to other types of compressors. For example, the compressor may be a diaphragm or membrane compressor in which the compression is produced by movement of a flexible membrane. The compressor may also be a hermetically sealed or semi-hermetically sealed compressor. In addition, the compressor types may include centrifugal compressors, diagonal or mixed flow compressors, axial flow compressors, rotary screw compressors, rotary vane compressors, and scroll compressors, among others.

The methods presently disclosed may also include generating a signal corresponding to the failure condition and alerting an operator or other personnel so that remedial action may be taken. Each of these systems and methods described above may also be implemented on a vehicle system such as the rail vehicle 106 described above. In still yet other embodiments, a test kit is provided that includes a controller having a memory and a processor configured to perform the methods described above.

In each of the embodiments presently disclosed, component fault data may be recorded. In one embodiment, component fault data may be stored in a database including historical compressor data. For example, the database may be stored in memory 134 of controller 130. As another example, the database may be stored at a site remote from rail vehicle 106. For example, historical compressor data may be encapsulated in a message and transmitted with communications system 144. In this manner, a command center may monitor the health of the compressor in real-time. For example, the command center may perform steps to diagnose the condition of the compressor using the compressor data transmitted with communications system 144. For example, the command center may receive compressor data including cylinder pressure data from rail vehicle 106, reservoir pressure, intermediate stage pressure, crankcase pressure, displacement of one or more pistons, and/or movement of the crankshaft to diagnose potential degradation of the compressor. Further, the command center may schedule maintenance and deploy healthy locomotives and maintenance crews in a manner to optimize capital investment. Historical compressor data may be further used to evaluate the health of the compressor before and after compressor service, compressor modifications, and compressor component change-outs.

If a leak or other fault condition exists, further diagnostics and response may be performed. For example, a potential faulty valve condition can be reported to notify appropriate personnel. In an embodiment, reporting is initiated with a signal output to indicate that a fault condition exists. The report is presented via display 140 or a message transmitted with communications system 144, as examples. Once notified, the operator may adjust operation of rail vehicle 106 to reduce the potential of further degradation of the compressor.

In one embodiment, a message indicating a potential fault is transmitted with communications system 144 to a command center. Further, the severity of the potential fault may be reported. For example, diagnosing a fault based on the above described methods may allow a fault to be detected earlier than when the fault is diagnosed with previously available means. In some applications, the compressor is permitted to continue operating when a potential fault is diagnosed in the early stages of degradation. In other applications, the compressor is stopped or maintenance may be promptly scheduled, such as when the potential fault is diagnosed as severe. In this manner the cost of secondary damage to the compressor can be avoided by early and accurate detection.

The severity of the potential fault may be determined based upon an analysis of one or more parameters from one or more diagnostic methods. For example, it may be more desirable to switch off the compressor than to have a degraded cylinder fail in a manner that may cause additional damage to the compressor. In one embodiment, a threshold value or one or more monitored parameters may be determined that indicates continued operation of the compressor is undesirable because the potential fault is severe. As one example, the potential fault may be judged as severe if the leakage of an exhaust valve exceeds a predetermined threshold.

In some embodiments, a request to schedule service is sent, such as by a message sent via communications system 144. Further, by sending the potential fault condition and the severity of the potential fault, down-time of rail vehicle 106 may be reduced. For example, service may be deferred on rail vehicle 106 when the potential fault is of low severity. Down-time may be further reduced by derating power of the compressor, such as by adjusting a compressor operating parameter based on the diagnosed condition.

In yet other embodiments, backup or redundant systems may be available. In an example, backup systems can be evaluated to determine if adequate substitute resources exist to replace the compromised compressor. In some instances, a pre-ordered list of backup systems is used to prioritize the use of backup systems, such as other compressors configured to supply compressed air to pneumatic devices on a plurality of rail vehicles. Various backup systems may be employed including stopping the faulty compressor and receiving charged air from another source. In one example, the other source is a compressor that is disposed on an adjacent locomotive engine. In another example, the other source is a redundant compressor on the same locomotive that is used for this purpose. The backup procedure can be designed to minimize negative system-wide consequences to operation of the locomotive. This is especially true for mission critical systems.

The aforementioned systems, components, (e.g., controller, detection component, pressure sensor, among others), and the like have been described with respect to interaction between several components and/or elements. It should be appreciated that such devices and elements can include those elements or sub-elements specified therein, some of the specified elements or sub-elements, and/or additional elements. Further yet, one or more elements and/or sub-elements may be combined into a single component to provide aggregate functionality. The elements may also interact with one or more other elements not specifically described herein.

In view of the exemplary devices and elements described supra, methodologies that may be implemented in accordance with the disclosed subject matter will be better appreciated with reference to the flow chart of FIG. 7. The methodologies are shown and described as a series of blocks, the claimed subject matter is not limited by the order of the blocks, as some blocks may occur in different orders and/or concurrently with other blocks from what is depicted and described herein. Moreover, not all illustrated blocks may be required to implement the methods described hereinafter. The methodologies can be implemented by a component or a portion of a component that includes at least a processor, a memory, and an instruction stored on the memory for the processor to execute.

FIG. 7 illustrates a flow chart of a method 700 for identifying a condition of a compressor based upon a measured crankcase pressure. At reference numeral 702, a crankcase pressure of a compressor can be monitored. At reference numeral 704, the monitored crankcase pressure can be analyzed. At reference numeral 706, a condition of the compressor can be identified based on the analysis of the monitored crankcase pressure.

In an embodiment, a method for a compressor is provided that includes monitoring a crankcase pressure of a compressor; analyzing the monitored crankcase pressure; and determining a condition of the compressor based on the analysis of the monitored crankcase pressure. In embodiment, the method can include analyzing the monitored crankcase pressure by calculating an average of the crankcase pressure over a time period; and comparing the average crankcase pressure over the time period to a nominal crankcase average pressure. In an embodiment, the method includes determining a condition of the compressor based on the difference between the calculated crankcase average pressure and the nominal crankcase average pressure. In an embodiment, the method includes determining the nominal crankcase average pressure from at least one of ambient air temperature and ambient air pressure. In an embodiment, the method includes determining the nominal crankcase average pressure from at least one of compressor speed, reservoir pressure, and oil temperature.

In an embodiment, the method includes analyzing the monitored crankcase pressure by identifying frequency content of the monitored crankcase pressure at one or more known frequencies. In an embodiment, the method includes determining the one or more known frequencies based on a rate at which the compressor is operated. In an embodiment, the method includes analyzing the monitored crankcase pressure by correlating the monitored crankcase pressure with an indication of the position of one or more pistons of the compressor during a time period in which the one or more pistons are operated. In an embodiment, the method includes determining a condition of the compressor by identifying a condition of one of a plurality of cylinders of the compressor based on a correlation of the monitored crankcase pressure and an indication of the position of the piston in the cylinder of the compressor.

In an embodiment, the method includes determining a condition of the compressor by identifying a piston blow-by condition of at least one cylinder of the compressor based on the analysis of the monitored crankcase pressure. In an embodiment, the method includes determining a condition of the compressor by identifying a crankcase breather valve failure based on the analysis of the monitored crankcase pressure. In an embodiment, the method includes monitoring the crankcase pressure of a compressor while a piston is cycled within a cylinder of the compressor in an unloaded condition. In an embodiment, the method includes monitoring the crankcase pressure of the compressor while a piston is cycled within a cylinder of the compressor in a loaded condition.

In an embodiment, the method includes monitoring the crankcase pressure of the compressor during a first time period during which a piston is cycled within a cylinder of the compressor in an unloaded; monitoring the crankcase pressure of the compressor during second time period during which the piston is cycled within the cylinder of the compressor in a loaded condition; and determining a condition of the compressor based on the analysis of the monitored crankcase pressure from the first time period and the second time period.

In an embodiment, the method includes generating a signal in response to determining a condition of the compressor based on the analysis of the monitored crankcase pressure. In an embodiment, the method includes reducing a duty cycle of the compressor in response to determining a condition of the compressor based on the analysis of the monitored crankcase pressure. In an embodiment, the method includes notifying personnel via one or more of an audio alarm, a visual alarm, a text message, an email, an instant message, or a phone call in response to determining a condition of the compressor based on the analysis of the monitored crankcase pressure.

In an embodiment, a controller that is operable to determine a condition of a compressor is provided in which the controller is configured to receive a signal corresponding to a monitored pressure within a crankcase of the compressor; analyze the monitored crankcase pressure; and identify a condition of the compressor based on the analysis of the monitored crankcase pressure. In an embodiment, the condition of the compressor is a piston blow-by condition of at least one cylinder of the compressor. In an embodiment, the condition of the compressor is a crankcase breather valve failure. In an embodiment, the controller is further configured to calculate an average of the crankcase pressure over a time period; and compare the average crankcase pressure over the time period to a nominal crankcase average pressure. In an embodiment, the controller is further configured to communicate with one or more crankcase pressure sensors and receive the signal corresponding to the monitored pressure from the one or more crankcase pressure sensors.

In embodiments, a system is disclosed. The system includes an engine; a compressor operatively connected to the engine, wherein the compressor includes a crankcase having a crankcase pressure sensor; a controller that is operable to determine a condition of the compressor, wherein the controller is configured to receive a signal corresponding to a monitored pressure within the crankcase of the compressor from the crankcase pressure sensor, analyze the monitored crankcase pressure; and determine a condition of the compressor based on the analysis of the monitored crankcase pressure.

In embodiments, a compressor system is disclosed that includes means for means for monitoring a crankcase pressure of a compressor (for example, a crankcase pressure of a compressor can be monitored by the pressure sensor 170, the sensor 172, the detection component 128, among others); means for analyzing the monitored crankcase pressure (for example, the analysis of the monitored crankcase pressure can be provided by the controller 130, the detection component 128, among others); and means for determining a condition of the compressor based on the analysis of the monitored crankcase pressure (for example, the condition of the compressor can be determined by the controller 130).

In an embodiment, a compressor can be provided that includes a sensor configured to measure pressure in a crankcase of a compressor and means for determining the position of a piston in a cylinder of the compressor, wherein the piston is operably connected to a crankshaft in the crankcase of the compressor. In the embodiment, the compressor can further include means for determining a condition of the compressor based on a correlation of the monitored crankcase pressure and an indication of a position of a piston in a cylinder of the compressor. Furthermore, the means for determining the position of a piston in a cylinder of the compressor can include a crankshaft position sensor.

As used herein, the terms “high pressure” and “low pressure” are relative to one another, that is, a high pressure is higher than a low pressure, and a low pressure is lower than a high pressure. In an air compressor, low pressure may refer to a pressure that is higher than atmospheric pressure, but that is lower than another, higher pressure in the compressor. For example, air at atmospheric pressure may be compressed to a first, low pressure (which is still higher than atmospheric pressure), and further compressed, from the first, low pressure, to a second, high pressure that is higher than the low pressure. An example of a high pressure in a rail vehicle context is 140 psi (965 kPa).

In the specification and claims, reference will be made to a number of terms that have the following meanings. The singular forms “a”, “an” and “the” include plural referents unless the context clearly dictates otherwise. Approximating language, as used herein throughout the specification and claims, may be applied to modify a quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term such as “about” is not to be limited to the precise value specified. In some instances, the approximating language may correspond to the precision of an instrument for measuring the value. Moreover, unless specifically stated otherwise, a use of the terms “first,” “second,” etc., do not denote an order or importance, but rather the terms “first,” “second,” etc., are used to distinguish one element from another.

As used herein, the terms “may” and “may be” indicate a possibility of an occurrence within a set of circumstances; a possession of a specified property, characteristic or function; and/or qualify another verb by expressing one or more of an ability, capability, or possibility associated with the qualified verb. Accordingly, usage of “may” and “may be” indicates that a modified term is apparently appropriate, capable, or suitable for an indicated capacity, function, or usage, while taking into account that in some circumstances the modified term may sometimes not be appropriate, capable, or suitable. For example, in some circumstances an event or capacity can be expected, while in other circumstances the event or capacity cannot occur—this distinction is captured by the terms “may” and “may be.”

This written description uses examples to disclose the invention, including the best mode, and also to enable one of ordinary skill in the art to practice the invention, including making and using a devices or systems and performing incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to one of ordinary skill in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differentiate from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims. 

What is claimed is:
 1. A method for a compressor, comprising: monitoring a crankcase pressure of a compressor; analyzing the monitored crankcase pressure; and identifying a condition of the compressor based on the analysis of the monitored crankcase pressure.
 2. The method of claim 1, wherein analyzing the monitored crankcase pressure comprises: calculating an average of the crankcase pressure over a time period; and comparing the average crankcase pressure over the time period to a nominal crankcase average pressure.
 3. The method of claim 2, wherein the condition of the compressor is identified based on a difference between the calculated crankcase average pressure and the nominal crankcase average pressure.
 4. The method of claim 2, further comprising identifying the nominal crankcase average pressure from at least one of ambient air temperature or ambient air pressure.
 5. The method of claim 2, further comprising identifying the nominal crankcase average pressure from at least one of compressor speed, reservoir pressure, or oil temperature.
 6. The method of claim 1, wherein analyzing the monitored crankcase pressure comprises identifying frequency content of the monitored crankcase pressure at one or more known frequencies.
 7. The method of claim 6, further comprising identifying the one or more known frequencies based on a rate at which the compressor is operated.
 8. The method of claim 1, wherein analyzing the monitored crankcase pressure comprises correlating the monitored crankcase pressure with an indication of the position of a piston of the compressor during a time period in which the piston is operated.
 9. The method of claim 8, wherein identifying the condition of the compressor further comprises identifying a condition of a cylinder of the compressor based on a correlation of the monitored crankcase pressure and an indication of the position of the piston in the cylinder of the compressor.
 10. The method of claim 1, wherein identifying the condition of the compressor comprises at least one of the following: identifying a piston blow-by condition of at least one cylinder of the compressor based on the analysis of the monitored crankcase pressure; or identifying a crankcase breather valve failure based on the analysis of the monitored crankcase pressure.
 11. The method of claim 1, wherein the crankcase pressure is monitored while a piston is cycled within a cylinder of the compressor in at least one of an unloaded condition or in a loaded condition.
 12. The method of claim 1, wherein: monitoring the crankcase pressure of the compressor comprises: monitoring the crankcase pressure during a first time period during which a piston is cycled within a cylinder of the compressor in an unloaded; and monitoring the crankcase pressure of the compressor during a second time period during which the piston is cycled within the cylinder of the compressor in a loaded condition; and the condition of the compressor is identified based on the analysis of the monitored crankcase pressure from the first time period and the second time period.
 13. The method of claim 1, further comprising generating a signal in response to identifying the condition of the compressor based on the analysis of the monitored crankcase pressure.
 14. The method of claim 13, further comprising notifying personnel with the signal, the signal comprising one or more of an audio alarm, a visual alarm, a text message, an email, an instant message, or a phone call.
 15. The method of claim 1, further comprising reducing a duty cycle of the compressor in response to identifying the condition of the compressor.
 16. A controller operable in association with a compressor, wherein the controller is configured to: receive a signal corresponding to a monitored crankcase pressure within a crankcase of the compressor; analyze the monitored crankcase pressure; and identify a condition of the compressor based on the analysis of the monitored crankcase pressure.
 17. The controller of claim 16, wherein the condition of the compressor is at least one of the following: a piston blow-by condition of at least one cylinder of the compressor; or a crankcase breather valve failure.
 18. The controller of claim 16, wherein for the analysis of the monitored crankcase pressure, the controller is configured to: calculate an average of the crankcase pressure over a time period; and compare the average crankcase pressure over the time period to a nominal crankcase average pressure.
 19. The controller of claim 16, wherein the controller is further configured to communicate with one or more crankcase pressure sensors and receive the signal corresponding to the monitored crankcase pressure from the one or more crankcase pressure sensors.
 20. A system, comprising: an engine; a compressor operatively connected to the engine, wherein the compressor includes a crankcase having a crankcase pressure sensor; and a controller configured to: receive a signal corresponding to a monitored crankcase pressure within the crankcase of the compressor from the crankcase pressure sensor; analyze the monitored crankcase pressure; and identify a condition of the compressor based on the analysis of the monitored crankcase pressure.
 21. The system of claim 20, wherein the condition of the compressor is at least one of the following: a piston blow-by condition of at least one cylinder of the compressor; or a crankcase breather valve failure.
 22. The system of claim 20, wherein the controller is further configured to communicate with a crankshaft position sensor to identify a position of a piston in a cylinder of the compressor, and wherein the controller is configured to analyze the monitored crankcase pressure based at least in part on the position of the piston. 